This invention relates to a vehicle suspension system and a control valve therefor.
It is known that when a vehicle such as an automobile travels around a corner, centrifical forces acting on the vehicle tend to cause body roll which if severe can cause instability. The problem is more pronounced with vehicles which have a relatively high center of gravity such as trucks or vans.
Australian Patent No. 618,732 (corresponding to WO 88/07455) discloses an antiroll suspension system for a vehicle. The system includes a pendulum operated control valve. The specification discloses several forms of control valve. The general object of the present invention is to provide an improved and simplified control valve which can be used in antiroll suspension systems of the type disclosed in the patent. Another object is to provide antiroll suspension incorporating the new form of control valve.
According to the present invention there is provided a control valve comprising a valve body, a valve element mounted for sliding movement in the valve body, a control arm, coupling means for translating rotational movement of the control arm to linear displacement of the valve element, to thereby selectively open and close valve ports in the valve body.
The invention also provides an antiroll suspension for a vehicle, said vehicle including a chassis, a pair of wheels mounted on axles, springs acting between the chassis and the axles, the suspension comprising a torsion bar mounted transversely of the vehicle for rotation about an axis, a first arm and a second arm extending from the bar, a third arm and a fourth arm pivotally connected to the first and second arms respectively, the third and fourth arms being coupled to the axis or the chassis of the vehicle wherein at least one of the arms includes an extensible strut which on operation thereof effectively alters the length of said at least one arm and control means to control extension and retraction of said at least one arm and rotation of the torsion bar generally in proportion to laterally directed centrifical forces acting on the vehicle and wherein the control means includes a control valve as defined above.